Bug#486754: dummy packages often cannot be safely removed as fast as they say

[jidanni@jidanni.org]

Also standardize dummy package Descriptions' wording via templates or
recommendations.

E.g., often they say "this is a dummy package and can safely be
removed", when in fact they should also say "after ... transition is
complete" (which by the way the end user doesn't know how to
determine), else removing will break dependencies.

P.S., apt-get autoremove doesn't know that some packages were
installed by dummy package vs. normal packages...